Performance Analysis of Single-Carrier and Multi-Carrier Schemes in a Non-Linear Terahertz Communication System

This study presents a systematic comparison of single-carrier modulation schemes versus multi-carrier scheme, i.e., Orthogonal Frequency Division Multiplexing (OFDM), for indoor terahertz communications in the 300 GHz band. The analysis incorporates real-world measurement data, accounting for practical channel conditions and system non-linearities. Our findings show that OFDM without clipping performs worse than single-carrier schemes, as it is more affected by the system non-linearities. However, with the application of amplitude clipping techniques, OFDM demonstrates enhanced resilience to terahertz channel characteristics and system non-linearity, particularly at higher signal-to-noise ratios (SNR). Results show that OFDM with a clipping ratio of 0.5 achieves a BER improvement of up to 20 % compared to single-carrier schemes under the same conditions. These results provide valuable insights into the trade-offs between single-carrier and multi-carrier modulation schemes for terahertz communications, guiding the design of future wireless systems.